188k views
5 votes
Cos(3x) = 1

1. Using an appropriate inverse trigonometric expression, write an equation that defines the value of 3x

2. Solve this equation to find all possible values of the angle 3x

3. Use algebra to find all values of x between 0 and 2pi that satisfy this equation

User Jonno
by
3.3k points

2 Answers

7 votes

Final answer:

The initial equation with cosine exceeding the range is incorrect. Correcting the range and using arccos to solve for the angle, we find all possible values of x considering the periodicity of the cosine function.

Step-by-step explanation:

The original equation presented by the student, cos(3x) = 11, contains an error since the cosine function can only have values between -1 and 1. However, moving forward with the concept of solving for angles using inverse trigonometric functions, we can consider a corrected equation such as cos(3x) = A, where A is within the correct range. We would then use the inverse cosine function (arccos) to find the angle, resulting in 3x = arccos(A). To find all values of x between 0 and 2π that satisfy this equation, we would first solve for 3x = arccos(A) and then divide the result by 3 to find x. Due to the periodic nature of the cosine function, additional solutions can be found by adding integer multiples of 2π to the obtained angles before dividing by 3.

User Please Delete Me
by
3.6k points
3 votes

Step-by-step explanation:

cos(3x) = 1

3x = 0 + 2kπ

x = 0 + 2kπ/3

x = 0, 2π/3, 4π/3, 2π

User JayL
by
3.3k points